A roller blind arrangement of this kind is known from DE 10 2008 012 202 A1 and comprises a roller blind web capable of being unwound from a winding shaft in order to shade a transparent roof section of the respective automobile and of being wound onto the winding shaft in order to not shade the transparent roof section. At each of its edges arranged laterally with respect to a vertical longitudinal center plane of the vehicle, the roller blind arrangement has a guide rail in which a respective lateral edge of the roller blind web is guided. In this way, the roller blind web can be kept tensioned in the transverse direction of the roller blind web, i.e. in the transverse direction of the vehicle. For actuation, the roller blind arrangement has a driving motor which drives two driving cables, which constitute the driving means of the roller blind web and each of which is guided in a guide rail toward a pull bar arranged at an edge of the roller blind web that faces away from the winding shaft. The driving cables, which are formed by so-called pitch cables and have a substantially round cross-section, simultaneously form lateral guide tapes of the roller blind web, and they do so in that the roller blind web is wrapped around the driving cables by means of a complex deflecting arrangement when entering the guide rail. The driving cables thus dig into the roller blind web via a rough, brush-like surface, which is formed by a plurality of fine bristles. The fact that the roller blind web wraps around the driving cables and the bristles dig into the roller blind web causes high wear of the roller blind web. Moreover, the deflecting arrangement for the roller blind web requires a large amount of constructional effort.
The object of the invention is to provide a roller blind arrangement of the kind mentioned above that allows simultaneous use of driving means as driving elements and as guide elements of the roller blind web at little constructional effort.
This object is attained according to the invention by the roller blind arrangement having the features of claim 1.
According to the invention, the roller blind web is pressed between the undersides of the driving means, which are formed by toothed belts, and the bottoms of the guide tracks or between the upper sides of the driving means and the roofs of the guide tracks within the guide tracks of the guide rails.
The guide tracks are adjusted to the cross-section of the toothed belts and thus have at least one groove section having a rectangular cross-section. This leads to an at least approximately U-shaped or an at least approximately invertedly U-shaped deflection of the roller blind webs within the guide tracks. When the roller blind web enters the guide tracks of the guide rails, the deflection is realized solely by the toothed belts, which enter the guide tracks at the same time and press the roller blind web into the guide tracks. The deflection allows the roller blind web to dig into the toothings, i.e. into the edges of the teeth of the toothings, which ensures that the roller blind web is tightly tensioned transverse to the pulling direction. The toothings of the toothed belts are formed at least on the toothed belt side with which the toothed belts press the roller blind web against the bottoms of the guide tracks or against the roofs of the guide tracks, i.e. on the undersides or on the upper sides of the toothed belts. The toothings of the toothed belts can thus engage directly into the material of the roller blind web and embed themselves there. At the same time, the toothed belts exert a strong retaining force onto the roller blind web. No separate deflecting means, such as guide surfaces or the like, are necessary to deflect the roller blind web into the U-shaped state or into the inverted U-shaped state. Instead, the deflection is realized solely by the force applied by the respective toothed belt from above or from below within the respective guide track of the guide rail. Since, additionally, the degree to which the roller blind web is deflected may be small, i.e. the depth of impression of the roller blind web into the guide track may be small and the material of the roller blind web is always somewhat elastic, crease-free winding-up of the roller blind web into a roller blind reel is ensured, too. Upon actuation, the toothed belts, which constitute the driving means for the roller blind web, can cause the roller blind web to be wound up or unwound, and they can do so at low forces.
Owing to the fabric tension of the roller blind web in the transverse direction of the roller blind, the toothed belts are each subjected to a torque about their respective longitudinal axis. The toothed belts then are supported on the walls of the guide track via their corner surfaces which face in the direction of the torque. In this way, twisting of the toothed belts in the guide tracks is prevented.
The arrangement of the toothings parallel to the plane of the unwound roller blind web allows each of the toothed belts to be deflected in a plane that is at a right angle to the plane of the unwound roller blind web so as to be able to go around any components of the automobile that are arranged in a straight line between the respective guide rail and a driving element for the respective toothed belt without disturbing the driving function. This means that the toothed belts are flexible in a direction that is at a right angle to the plane of the roller blind web, allowing them to be guided around respective components. This, in turn, has the result that the roller blind reel in particular can be arranged in this direction in an optimized manner in terms of installation space and the toothed belts can be guided around the roller blind reel. For example, the roller blind reel can be stored in an installation space of the guide rails and not or only slightly penetrate a rail bottom when the roller blind web is in the wound-up state. This has a positive effect on the maximum headroom realizable in the vehicle interior.
In a preferred embodiment of the roller blind arrangement according to the invention, each toothed belt is driven by means of a driving pinion whose plane is located at least approximately in the plane of the respective toothed belt. The driving pinion can in particular be integrated into an installation space of a guide rail associated with the respective toothed belt or in a front-side attachment of said guide rail. Thus, an elaborate deflection of the of the toothed belt in the transverse direction of the roller blind arrangement is unnecessary, which, in turn, facilitates constructional implementation of the roller blind arrangement according to the invention.
In a specific embodiment of the roller blind arrangement according to the invention, the two driving pinions, each of which drives one of the toothed belts, are driven by a shared driving motor. The driving motor can be coupled to the two driving pinions via rigid or flexible driving shafts.
In an alternative embodiment of the roller blind arrangement according to the invention, each driving pinion is driven by a separate driving motor. In this case, the driving motors are preferably fixed to the guide rails or to front-side attachments of the guide rails, the driving pinions for the toothed belts also being integrated in said attachments.
The arrangement of the toothed belt according to the invention, i.e. the orientation of the teeth of the toothing parallel to the plane of the roller blind web, allows the driving pinions to be variably arranged at different points within the roller blind arrangement. For example, the driving pinions may be arranged on the side of the roller blind reel that faces away from the guide rails, in which case the toothed belts engage over and/or under the roller blind reel. The toothed belts are thus guided past the roller blind reel toward the guide rails in order to there guide the roller blind web in den guide tracks and to engage with the roller blind web.
In an embodiment of the roller blind arrangement according to the invention that consumes little installation space, the driving pinions can be arranged between the roller blind reel and the guide rails. In this case, the toothed belts do not have to be guided around the roller blind reel, which means that no additional installation space has to be reserved for this measure.
In another alternative embodiment of the roller blind arrangement according to the invention, the driving pinions are arranged on the sides of the guide rails that face away from the roller blind reel. In this embodiment, it may be necessary for the toothed belts to be guided around a vehicle component, such as a wind deflector of a roof opening system, in corresponding guide channels, which is made possible by the horizontal arrangement of the toothed belts, i.e. by aligning the toothing of the toothed belts parallel to the plane of the roller blind web.
To ensure proper function of the roller blind arrangement according to the invention, a guide channel for an exiting end of the respective toothed belt is formed on each of the guide rails in an advantageous embodiment of the roller blind arrangement according to the invention.
For example, each guide channel is formed by a guide tube fixed to the respective guide rail. The guide tube can be made of plastic.
In a preferred embodiment of the roller blind arrangement according to the invention, each guide track has a substantially rectangular cross-section which corresponds to the cross-section of the respective toothed belt, the roller blind web being introduced into the guide tracks via a respective lateral slot and being arranged between the respective guide rail and the respective toothed belt, or more precisely its toothing, within the guide tracks.
To be able to realize the at least approximately U-shaped deflection or the invertedly U-shaped deflection of the roller blind web in the guide tracks, the slot is advantageously spaced apart from the bottom or from the roof of the respective guide track, respectively.
The slot via which the roller blind web is introduced into the respective guide track can be spaced apart from both the bottom and the roof of the respective guide track.
In a preferred embodiment of the roller blind arrangement according to the invention, however, the slot is spaced apart either from the bottom or from the roof of the respective guide track and extends as far as to the roof or to the bottom of the respective guide track, respectively.
This means that it is generally conceivable for the guide track, taking into account the opening defined by the slot, to have a circumferential wall that has an at least approximately C-shaped or, in the broadest sense, G-shaped cross-section.
To be able to substantially preclude undesired wedging or catching of an edge portion of the roller blind web, i.e. to improve guiding of the roller blind web in the guide rails, each guide track preferably has a tongue guide at the side that faces away from the slot, edge strips of the roller blind web engaging into said tongue guides.